Periampullary pancreatic somatostatinoma.

BACKGROUND: Somatostatinomas involving the gastrointestinal tract are extremely rare neoplasms that typically present with indolent, nonspecific symptoms in the absence of systemic neuroendocrine manifestations that characterize the somatostatinoma syndrome. Because of a relatively large size at the time of presentation (average diameter of 5 cm) and common location within the head of the pancreas, the Whipple procedure (pancreaticoduodenectomy) serves as the predominant modality for curative and palliative surgical approaches.

METHODS: Two cases of somatostatinoma involving the minor duodenal papilla with concomitant pancreatic divisum were reviewed, with a general overview of this unique islet cell tumor.

RESULTS: Unlike typical somatostatinomas, these two tumors were subcentimeter in size but were associated with synchronous regional metastasis.

CONCLUSIONS: Somatostatinomas are often associated with regional and/or portal metastases at the time of diagnosis, and only 60% to 70% of surgical cases result in complete tumor resection. Predictors of an unfavorable prognosis include size >3 cm, poor cytological differentiation, regional and/or portal metastasis, and incomplete surgical resection. Even in the presence of synchronous metastases, the 5-year overall survival for patients with somatostatinoma is approximately 40%. Currently, there are no clinical trials demonstrating significant improvement in survival with the use of adjuvant therapy.